Research Roundup: Drawing closer to curing the organ transplant shortage, using dengue antibodies to minimize the effects of Zika virus and more!

Welcome to this week’s Research Roundup. These Friday posts aim to inform our readers about the many stories that relate to animal research each week. Do you have an animal research story we should include in next week’s Research Roundup? You can send it to us via our Facebook page or through the contact form on the website.

Scientists grow bullish on pig-to-human transplants. Researchers give hope to those desperately waiting for an organ transplant. Although the technical skill in organ transplant has been well developed, minimizing the immune response for organs transplanted from one species to another has not. Recently, researchers have been able to lessen, although still not eliminate, the dangerous immune response that transplanted pig organs cause in monkeys. At the University of Munich, a cardiac surgeon, Paolo Brenner, reported results of the first animal to hit a milestone for determining whether a xenotransplantation approach is safe enough to try in humans. According to Immunologist David Cooper, University of Alabama in Birmingham, the new immunosuppressant drug regimens, genetically engineered pigs, and the use of gene-editing tools has increased the ability to safely transplant organs from one species to another. This leads to the possibility of, at least, temporary organ transplants while a patient is waiting for a human organ to be available. This can improve the quality of life for those awaiting kidney transplants and even extend the life for those with more urgent needs for life saving organ transplants.

Genetically engineered pigs produced in Munich, Germany, were recently used in a record-breaking baboon heart transplant. Credit: Jan-Michael Abicht

Common antidepressant found to reduce belly fat in older mice. Visceral fat, as compared to subcutaneous fat, is generally considered to be deadly, being linked to heart disease and type 2 diabetes. New research suggests that it is inflammation of immune cells which may lead to the accumulation of visceral fat, for example in the belly area. Christina Camel and her team at the Yale school of Medicine used young and old mice, isolated the macrophages from within the fat tissue, and then sequenced DNA from these cells. They found the macrophages in the older mice expressed more genes that prevent catecholamines, a set of molecules that spread signals between nerve cells. “The genes do this by activating an enzyme that suppresses these neurotransmitters. The boosted activity of this enzyme in aged immune cells in the belly fat of older mice effectively block signals telling the body that there is fat there that is available to burn for energy.” The drug used to accomplish this was “a common antidepressant called clorgyline, which is given to some people because low levels of catecholamine have been linked to symptoms of depression.” This research was published in the journal Nature.

New technique turns mouse brains transparent. Stroke is the leading cause of disability and the second leading cause of death worldwide. During a stroke, the blood supply to the brain is cut off, which prevents oxygen and vital nutrients from reaching cells. To understand this process, researchers typically examine 2D images of brain slices under a microscope. Now, a new technique has been developed where a fluorescent gel is injected into the hearts of mice and pumped through the body. The brain is then removed and soaked in chemicals, which leave the brain completely transparent. A laser is used to illuminate the fluorescent gel and provide a 3D image of the entire brain. In the brains of mice that had a stroke, researchers could see how the blood supply is cut off, and how surviving blood vessels reorganize. This research was published in the Journal of Cerebral Blood Flow & Metabolism.

Image source: Antonino Paolo Di Giovanna et al./CC BY-NC-ND 4.0.

Transplants of stem cells “cure” anemia in mice. Chronic kidney disease affects 30 million humans in the USA alone. Anemia is the decrease in total red blood cells. People whose kidneys are damaged can develop anemia, as the kidneys are responsible for making the hormone erythropoietin (EPO) that is key to triggering the production of red blood cells. This means the patient lacks enough red blood cells to carry oxygen around the body as effectively. In the present study, stem cells from human cord blood were induced into becoming pluripotent cells that were then coaxed into becoming cells that produce EPO. The cells were transplanted in the kidney cavities of mice with a form of anemia. Within 4 weeks, EPO levels were 20 times higher than those in controls. “Just one transplant of the human EPO-producing cells treated kidney anaemia in mice, keeping their haemoglobin levels in the normal range for the remaining 7-month lifespan of the animals,” says Kenji Osafune, of Kyoto University in Japan, who led the team. This research was published in the journal, Science Translational Medicine.

Anti-Dengue Antibody protects against Zika Virus Infection. Dengue and Zika are caused by related viruses, and as such, Professor Diamond and co-authors reasoned that an antibody, EDE1-B10, that prevents dengue disease may do the same for Zika. To accomplish this they infected nonpregnant adult mice with Zika and then administered the EDE1-B10 antibody in as series of experiments. They found that that for the antibody to effectively protect fetuses from Zika infection, it must be administered soon after infection.“Such a goal may be unrealistic clinically because women rarely know when they get infected,” the scientists noted.“However, giving women the antibody as soon as they know they are pregnant could provide them with a ready-made defense against the virus should they encounter it.” This research was published in the journal Nature Immunology.